Radiation-emitting semiconductor element and method for producing the same

ABSTRACT

This invention describes a radiation-emitting semiconductor component based on GaN, whose semiconductor body is made up of a stack of different GaN semiconductor layers ( 1 ). The semiconductor body has a first principal surface ( 3 ) and a second principal surface ( 4 ), with the radiation produced being emitted through the first principal surface ( 3 ) and with a reflector ( 6 ) being produced on the second principal surface ( 4 ).  
     The invention also describes a production method for a semiconductor component pursuant to the invention. An interlayer ( 9 ) is first applied to a substrate ( 8 ), and a plurality of GaN layers ( 1 ) that constitute the semiconductor body of the component are then applied to this. The substrate ( 8 ) and the interlayer ( 9 ) are then detached and a reflector ( 6 ) is produced on a principal surface of the semiconductor body.

[0001] This invention relates to a radiation-emitting semiconductorcomponent pursuant to the preamble of Patent claim 1 and a method forproducing it pursuant to the preamble of Patent claim 8 or 18.

[0002] Radiation-emitting semiconductor components based on GaN aredisclosed, for example, by U.S. Pat. No. 5,210,051. Such semiconductorcomponents contain a semiconductor body with an active GaN layer that isapplied to an SiC substrate. The semiconductor body is contacted on thefront on the light-emitting GaN layer and on the back on the SiCsubstrate.

[0003] It is also disclosed by U.S. Pat. No. 5,874,747, for example, howto use related nitrides and ternary or quaternary mixed crystals basedon them instead of GaN. Included among them in particular are thecompounds AlN, InN, AlGaN, InGaN, INAlN, and AlInGaN.

[0004] The term “III-V nitride semiconductor” as used below refers tothese ternary and quaternary mixed crystals as well as to galliumnitride itself.

[0005] It is also known how to produce GaN semiconductor crystals byepitaxy. A sapphire crystal or SiC is ordinarily used as substrate.According to U.S. Pat. No. 5,928,421, an SiC substrate is preferred withregard to avoiding lattice defects, since GaN layers grown on sapphirehave a large number of lattice defects because of the relatively largelattice mismatch between sapphire and GaN.

[0006] One drawback of radiation-emitting GaN semiconductor componentsconsists of the fact that at the surface at which the radiation producedin the semiconductor body is emitted, a large refractive indexdiscontinuity occurs at the transition from semiconductor body to thesurroundings. A large refractive index discontinuity leads to aconsiderable fraction of the radiation being reflected back into thesemiconductor body and to the radiation yield of the component therebybeing reduced.

[0007] One cause of this is the total reflection of the radiationproduced at the emission surface. Light rays are completely reflectedback into the semiconductor body if the angle of incidence of the lightrays at the emission surface is greater than the angle of totalreflection, each based on the normal to the surface. As the differencebetween the refractive index of the semiconductor body and that of thesurroundings increases, the angle of total reflection decreases and thefraction of totally reflected radiation rises.

[0008] Light rays whose angle of incidence is smaller than the angle oftotal reflection are also partially reflected back into thesemiconductor body, with the back-reflected fraction becoming larger asthe difference between the refractive indices of the semiconductor bodyand of the surroundings increases. A large refractive indexdiscontinuity, such as that occurring with GaN components, thereforeleads to large reflection losses at the emission surface. Theback-reflected radiation is partially absorbed in the semiconductor bodyor escapes at surfaces other than the emission surface, so that theoverall radiation yield is reduced.

[0009] One means of increasing the radiation yield consists of applyinga reflector to the substrate of the semiconductor body. This is shown,for example, in DE 43 05 296. This again points the radiationback-reflected into the semiconductor body in the direction of theemission surface, so that the back-reflected portion of the radiation isnot lost but is at least partially likewise emitted after one or moreinternal reflections.

[0010] In the case of radiation-emitting GaN components pursuant to thestate of the art, it is a drawback in this regard to use an absorbingsubstrate such as SiC, for example. The radiation reflected back intothe semiconductor body is absorbed in large part by the substrate, sothat it is impossible to increase the radiation yield by means of areflector.

[0011] U.S. Pat. No. 5,786,606 discloses a method for producingradiation-emitting semiconductor components based on GaN in which an SiClayer is first grown by epitaxy on a SIMOX substrate (Separation byIMplantation of OXygen) on an SOI substrate (Silicon On Isolator). Aplurality of GaN-based layers are then deposited on the SiC layer.

[0012] However, the radiation yield of the component is reduced by theSiC layer, since a portion of the radiation produced is absorbed in theSiC layer. Also, the epitaxial formation of an SiC layer with adequatecrystal quality requires a high production cost.

[0013] The task underlying this invention is to provide a III-V nitridesemiconductor component with increased light yield. It is also thepurpose of this invention to develop a method for producing suchsemiconductor components.

[0014] This task is accomplished by a semiconductor component pursuantto claim 1 and a production method pursuant to claim 8 or 18.

[0015] Beneficial refinements of the invention are the objects ofSubclaims 2 to 7. Subclaims 9 to 17 and 19 to 31 describe beneficialforms of embodiment of the production process pursuant to claim 8 and/orclaim 18.

[0016] The invention provides that the radiation-emitting semiconductorcomponent is developed as a thin-layer component that in particular hasno radiation-absorbing substrate. The semiconductor body of thecomponent is made up of a stacked plurality of different III-V nitridesemiconductor layers. In operation, an active semiconductor layer basedon GaN or on a related nitride produces electromagnetic radiation thatis emitted through a first principal surface of the stack. A reflectoris applied to a second principal surface of the stack, so that a portionof the radiation that is initially reflected back into the semiconductorbody during the emission is again pointed toward the emission surface bymeans of this reflector.

[0017] In this way, in addition to the primarily emitted fraction of theproduced radiation, another portion is emitted after one or moreinternal reflections at the reflector. Overall, the degree of emissionis thus increased compared to a GaN semiconductor component pursuant tothe state of the art.

[0018] In a preferred embodiment, the GaN-based semiconductor layersconsist of GaN, AlN, InN, AlGaN, InGaN, InAlN, or AlInGaN. By usingthese materials, the central wavelength of the radiation produced can beset within a broad range of the visible spectral region down to theultraviolet spectral region. Blue and green LEDs, UV LEDs, andcorresponding laser diodes can thus be realized with this invention withparticular advantage.

[0019] In an especially preferred embodiment, the reflector can beproduced by a metallic contact surface. This serves both as reflectorand for electrical contact with the semiconductor body. It is beneficialwith this embodiment that no other devices are needed on the reflectorside for contacting the semiconductor body. Al and Ag, as well as Al andAg alloys, are particularly suitable as material for the contactsurfaces.

[0020] In another advantageous embodiment, the reflector can also bemade by dielectric vapor deposition. Such vapor deposition can beperformed by applying a sequence of layers of SiO₂ or TiO₂ to thesemiconductor body. With dielectric vapor deposition, a loss-freereflection in a broad wavelength region can advantageously be produced.

[0021] In a preferred refinement, the reflector has a transparent firstlayer applied to the second principal surface, and a second reflectinglayer applied to this one. This permits optimizing the contact layer ina simple manner both with regard to its electrical characteristics andto its reflection characteristics.

[0022] In another preferred embodiment, the entire free surface of thesemiconductor body or a subregion of it is roughened. This roughinginterferes with total reflection at the emission surface and the opticaldegree of emission is thereby further increased.

[0023] In the production method pursuant to the invention, an interlayeris first applied to a substrate. A plurality of different III-V nitridesemiconductor layers are then deposited on this interlayer. These layersconstitute the semiconductor body of the component. In the next step,the substrate including the interlayer is then stripped from the stackof 111-V nitride layers thus formed. In a further step, a reflector isapplied to one of the two principal surfaces of the semiconductor body.

[0024] In another embodiment, an Si substrate is used, on which isapplied an SiC interlayer. SiC is particularly suitable for theproduction of GaN-based components, since it has a lattice constantsimilar to that of GaN, so that layers based on GaN deposited on SiChave a small number of lattice defects.

[0025] In another especially preferred embodiment, the interlayer isapplied by a wafer-bonding method and is then thinned. When using an Sisubstrate and an SiC interlayer, the Si wafer can advantageously bebonded to the SiC wafer by making an SiO₂ layer.

[0026] Alternatively, the interlayer can be grown by epitaxy, by whichespecially homogeneous interlayers can be produced.

[0027] In another preferred embodiment, the reflector is made byapplying a reflecting metal contact to the GaN semiconductor body. Agand Al as well as Ag and Al alloys are especially suitable as materialsfor the metal contact because of their reflectivity and bondingcharacteristics.

[0028] Another embodiment of the production method consists of makingthe reflector as a dielectric mirror in the form of a plurality ofdielectric layers, which results in the benefits of a dielectricreflector described above.

[0029] In an especially preferred refinement of the invention, theproduction method is continued by roughening the semiconductor body,with the entire free surface of the semiconductor body or subregionsthereof being roughened. Especially effective roughening with regard toincreasing the yield of light is produced by etching the semiconductorbody or by a sand-blasting method.

[0030] In another particularly preferred embodiment, a mask layer isapplied to the interlayer prior to the deposition of the III-V nitridelayers. This mask layer structures the layers and in particular itseparates the III-V nitride layers into several discontinuous regions.This very beneficially prevents cracking and detachment of theinterlayer from the substrate. An oxide mask is advantageously made asthe mask, especially when using SiC as the interlayer material.

[0031] In another production method pursuant to the invention, aplurality of III-V nitride layers are applied by epitaxy to a compositesubstrate that has a substrate body and an interlayer, with thecoefficient of thermal expansion of the substrate body being similar toor greater than the coefficient of thermal expansion of the III-Vnitride layers. A composite substrate in this context means a substratethat contains at least two regions, the substrate body and theinterlayer, and that as such represents the starting substrate for theepitaxial process. In particular, the interlayer is not applied to thesubstrate body by epitaxy, but preferably by a wafer-bonding method.

[0032] With such a composite substrate, the thermal properties aredetermined above all by the substrate body, while the epitaxy surfaceand especially its lattice constant are largely independently fixed bythe interlayer. Thus the interlayer can beneficially be optimallymatched to the lattice constant of the layers to be applied. At the sametime, the use of a substrate body with a sufficiently high coefficientof thermal expansion prevents the development of tensile stresses in theGaN-based layers in the cooling phase after application, and theresulting formation of cracks in the layers. Therefore, the interlayeris advantageously made so thin that the coefficient of thermal expansionof the entire composite substrate corresponds essentially to thecoefficient of expansion of the substrate body. The substrate body inthis case is typically at least twenty times as thick as the interlayer.

[0033] In an advantageous configuration of the invention, the substratebody contains SiC, preferably polycrystalline (poly-SiC), sapphire, GaN,or AlN. The coefficient of thermal expansion of SiC is similar to thecoefficient of expansion of GaN-based materials, while the othermaterials mentioned have larger coefficients of thermal expansion thanGaN-based materials. Thus cracking of the epitaxially applied layersduring cooling is advantageously avoided.

[0034] In a preferred configuration of the invention, the interlayercontains SiC, silicon, sapphire, MgO, GaN, or AlGaN. These materials areespecially suitable for producing an essentially monocrystalline surfacewith a lattice constant matching that of GaN. An Si(111) surface or amonocrystalline SiC surface is preferably used as the epitaxy surface onwhich the GaN-based layers are grown.

[0035] In an advantageous refinement of the invention, the GaN-basedlayers are deposited on a composite substrate in which the interlayer isapplied to the substrate body by a wafer-bonding method. A bondinglayer, for example of silicon oxide, is produced between the substratebody and the interlayer.

[0036] A number of material systems can beneficially be combined withwafer-bonding procedures, without being limited by materialincompatibilities, as for example in the case of the epitaxialapplication of an interlayer on a substrate body.

[0037] To obtain a sufficiently thin interlayer, a thicker interlayercan also first be bonded to the substrate body, which is then thinned tothe necessary thickness, for example by grinding or splitting.

[0038] In a beneficial refinement of the invention, a mask layer isproduced on the composite substrate before the deposition of the III-Vnitride layers, so that the III-V nitride layers grow only on theregions of the epitaxial surface that are not covered by the mask. Theselayers are thereby advantageously interrupted in the plane of the layer,and additional protection against tensile stress and the associatedcracking is thus achieved.

[0039] Another preferred configuration of the invention consists ofstructuring the III-V nitride layers into individual semiconductor layerstacks after deposition on the composite substrate. A support is thenapplied to the III-V nitride semiconductor layer stack and the compositesubstrate is detached. The composite substrate in this way can then bereused, at least in part. This represents a special advantage for SiCsubstrate bodies, the production of which involves very high costs. Athin-layer component can also be made in this way. A thin-layercomponent means a component that contains no epitaxy substrate.

[0040] In the case of radiation-emitting semiconductor components, theradiation yield is thus increased since absorption of the radiationproduced in the epitaxy substrate, such as that occurring in particularwith SiC substrates, is avoided.

[0041] The so-called rebonding of the semiconductor layer stack justdescribed, from the composite substrate to a support, can also beperformed in two steps with the invention, with the GaN-basedsemiconductor layer stack first being bonded to an intermediate supportand then to the actual carrier, so that the actual carrier then takesthe place of the composite substrate. Semiconductor layer stacks made inthis way advantageously have a layer sequence corresponding to GaN-basedsemiconductor bodies with epitaxy substrate pursuant to the state of theart, so that the same subsequent processing steps can be used for bothlayer stacks, for example singling, contacting, and incorporation into ahousing.

[0042] In the production method, a reflector layer is produced on thesemiconductor layer stack to increase the radiation yield. The radiationyield in the case of GaN-base semiconductor components in large part islimited by reflection at the interfaces of the semiconductor body. Inthe case of radiation-emitting semiconductor bodies with no absorbingsubstrate, the radiation fractions reflected at the emission surfacescan advantageously be pointed back to the emission surface again by areflector layer. This further increases the radiation yield.

[0043] The reflector layer is preferably made as a metallic layer, whichcontains aluminum, silver, or an appropriate aluminum or silver alloy,for example.

[0044] Such a metallic layer can be used advantageously as a contactsurface at the same time. Alternatively, the reflector layer can also bemade by dielectric vapor deposition in the form of a plurality ofdielectric layers.

[0045] In an advantageous refinement of the invention, at least aportion of the surface of the semiconductor layer stack is roughened.This interferes with total reflection at the surface and thus theradiation yield is increased. The roughening is preferably done byetching or by a sand blasting process.

[0046] Other features, advantages, and uses are found in the followingdescription of four examples of embodiment, in combination with FIGS. 1to 7. The figures show:

[0047]FIG. 1 a schematic cross-sectional view of a first embodiment of asemiconductor component pursuant to the invention,

[0048]FIG. 2 a schematic cross-sectional view of a second embodiment ofa semiconductor component pursuant to the invention,

[0049]FIG. 3 a schematic illustration of a first example of embodimentof a first production method pursuant to the invention, and

[0050]FIG. 4 a schematic illustration of a first example of embodimentof a second production method pursuant to the invention.

[0051]FIG. 5 a schematic cross-sectional illustration of another exampleof embodiment of a production method pursuant to the invention,

[0052]FIG. 6 a schematic cross-sectional illustration of another exampleof embodiment of a production method pursuant to the invention, and

[0053]FIG. 7 a schematic cross-sectional illustration of another exampleof embodiment of a production method pursuant to the invention.

[0054] The radiation-emitting semiconductor component shown in FIG. 1has a plurality of different semiconductor layers 1 in stackedarrangement that consist of GaN or of a ternary or quaternary compoundbased thereon. In operation, an active zone 2 is formed within theselayers in which the radiation 5 is generated.

[0055] The stack of layers is bounded by a first principal surface 3 anda second principal surface 4. The radiation 5 produced is essentiallyemitted through the first principal surface 3 to the adjoiningsurroundings.

[0056] A reflector 6 is applied to the second principal surface 4,formed from an Ag layer vapor-deposited on the semiconductor body.Contact with the semiconductor body is made on the emission side by thecontact surface 12, and on the reflector side by the Ag reflector layer.Contacting can be achieved on the reflector side, for example, bycontacting the semiconductor body on the reflector side with a metalbody that serves both as carrier and to infeed current.

[0057] The reflector 6 causes a portion of the radiation 5 that isreflected back into the semiconductor body at the first principalsurface 3 during emission, to be reflected back toward the firstprincipal surface 3, so that the amount of radiation emitted through thefirst principal surface 3 is increased overall. This increase is madepossible by the fact that the component is made as a thin-layercomponent with no radiation-absorbing substrate, and the reflector 6 isapplied directly to the GaN semiconductor body.

[0058] The example of embodiment of a semiconductor component pursuantto the invention shown in FIG. 2 differs from the component shown inFIG. 1 in that the surface of the semiconductor body has a roughening 7.This roughening 7 causes scattering of the radiation 5 at the firstprincipal surface 3, so as to interfere with total reflection at thefirst principal surface 3. Furthermore, this scattering prevents theradiation produced by continuing reflections of the same kind from beingguided between the two principal surfaces 3 and 4 and the reflector 6,in the way of an optical waveguide, without leaving the semiconductorbody. Thus, the roughening 7 further increases the light yield.

[0059]FIG. 3 shows a first example of embodiment of a production methodpursuant to the invention. The starting point is an Si substrate 8, FIG.3a. In a first step, an SiC interlayer 9 is applied to this Si substrateby a wafer-bonding method, with an SiO₂ layer 10 being developed betweenthe two substrates, FIG. 3b. In the next step, the SiC substrate 9 isthinned to a few micrometers, FIG. 3c. A plurality of different GaNsemiconductor layers 1 are epitaxially deposited on the thinned SiCsubstrate 9 by an MOCVD method, which constitute the semiconductor bodyof the component pursuant to the invention, FIG. 3d. After producing theGaN layer stack, the Si substrate 8 and the SiC interlayer 9 areremoved, FIG. 3e. A reflecting metallic contact surface 6, consisting ofan Ag or Al alloy, is then vapor-deposited on a principal surface 4 ofthe GaN semiconductor body, FIG. 3f.

[0060] To minimize total reflection at the first principal surface 3,the semiconductor body can then be roughened by a sandblasting procedureor by etching with a suitable etching mixture.

[0061] The embodiment of a production method pursuant to the inventionshown in FIG. 4 is analogous to the first example of embodimentdescribed above up to and including the thinning of the SiC substrate 9(FIGS. 4a to 4 c). In contrast to it, an oxide mask 11 is applied to theSiC layer 9 prior to the deposition of the GaN layers 1, FIG. 4d. Thisoxide mask 11 causes the GaN layers 1 to grow in the next step only onthe subregions of the SiC interlayer not covered by the mask.

[0062] Since the GaN layers 1 formed in this way are interrupted alongthe plane of the layer, stresses from the differing coefficients ofthermal expansion of SiC and GaN that occur especially during thecooling of the component after its production, are reduced. This leadsadvantageously to less cracking in the GaN layers 1 and suppressesdelamination of the SiC interlayer 9 from the substrate. The reflector6, FIG. 4g, is produced as described above.

[0063] In the production method shown in FIG. 5, a composite substrateis used with a substrate body 21 of poly-SiC, to which a monocrystallineSiC interlayer 22 is bonded by a known method. To this end, a bondinglayer 23, for example of silicon oxide, is formed between the substratebody 21 and the interlayer 22, FIG. 5a.

[0064] A plurality of GaN-based layers 24 are grown by epitaxy on thiscomposite substrate, FIG. 5b. The structure of the sequence of layers issubject to no restrictions in principle.

[0065] Preferably an active layer is formed to produce radiation, whichis surrounded by one or more mantle layers and/or waveguide layers. Theactive layer can be made up of a number of thin individual layers in theform of a mono quantum well or multiple quantum well structure.

[0066] It is also advantageous first to produce a buffer layer, forexample based on AlGaN, on the interlayer 22, by which an improvedlattice match and higher wettability with regard to the following layerscan be achieved. To increase the electrical conductivity of such abuffer layer, electrically conductive channels can be enclosed in thebuffer layer, for example based on InGaN.

[0067] The GaN-based layers 24 are then divided into individualsemiconductor layer stacks 25 by lateral structuring, preferably by mesaetching, FIG. 5c.

[0068] In the next step, FIG. 5d, a carrier 26, for example of GaAs or amaterial transparent to the radiation produced, is applied to thesesemiconductor layer stacks 25.

[0069] The composite substrate including the interlayer 22 is thereupondetached from the semiconductor layer stacks 25, FIG. 5e. This can bedone, for example, by an etching process in which the interlayer 22 orthe bonding layer 23 is destroyed. The substrate body 21 canadvantageously be reused in another production cycle.

[0070] Contact surfaces 30 are then applied to the thin-layersemiconductor body 25 thus formed, FIG. 5f. The semiconductor layerstack 25 is then singled, FIG. 5g, and further processed in the usualway.

[0071] In the production method illustrated in FIG. 6, a compositesubstrate is again used, which is essentially made up of a poly-SiCsubstrate body 21 and an Si(111) interlayer 22. The interlayer 22 isapplied to the substrate body 21 using a wafer-bonding method, with theproduction of a silicon oxide bonding layer 23, FIG. 6a.

[0072] A plurality of GaN-based layers are then grown in turn on thiscomposite substrate, FIG. 6b, which is then provided with a contactlayer 28, for example made of platinum, FIG. 6c.

[0073] The GaN-based layers 24 are then divided into individualsemiconductor layer stacks 25 by etch structuring, FIG. 6d.

[0074] For protection, a passivating layer 31, preferably based onsilicon nitride, is then applied to these semiconductor layer stacks 25formed in this way, FIG. 6e.

[0075] Bonding solder 32 is then deposited on each region of the contactlayer 28 not covered by the passivating layer, and on it is deposited areflector 29 of a silver or aluminum alloy, FIG. 6f.

[0076] The semiconductor layer stacks 25 with the reflector 29 are thenrebonded eutectically to a carrier 26, FIG. 6g.

[0077] In the following step, FIG. 6h, the substrate body 21 is removedand can thus be reused.

[0078] The individual semiconductor layer stacks are then provided withcontact surfaces 30 on their tops, FIG. 6i. The semiconductor layerstacks can then by singled and optionally incorporated into a housing(not shown).

[0079] The example of embodiment of a production method pursuant to theinvention shown in FIG. 7 represents a variant of the previous examplesof embodiment.

[0080] Again, as already described, a composite substrate is used as theepitaxy substrate, FIG. 7a.

[0081] Before depositing the GaN-based layer 24, a mask layer 27 isapplied to the epitaxy surface of the interlayer 22, FIG. 7b. TheGaN-based layers 24 thus grow only on the regions of the epitaxy surfacethat are not covered by the mask layer 27 (epitaxy windows), FIG. 7c.The GaN-based layers 24 are thereby interrupted in the layer plane. Thisadditionally avoids tensile stresses in the epitaxially deposited layersin the cooling phase.

[0082] The production method can then be continued as in the otherexamples of embodiment.

[0083] The explanation of the invention with reference to the describedexamples of embodiment naturally does not imply any limitation of theinvention thereto, but it comprises all forms of embodiment that makeuse of the inventive concept.

1. Radiation-emitting semiconductor component whose semiconductor bodyis made up of a stack of different III-V nitride semiconductor layers(1) and that has a first principal surface (3) and a second principalsurface (4), with at least a portion of the radiation (5) produced beingemitted through the first principal surface (3), characterized by thefact that a reflector (6) is applied to the second principal surface(4).
 2. Radiation-emitting semiconductor component pursuant to claim 1,characterized by the fact that the semiconductor layers (1) consist ofGaN, AlN, InN, AlGaN, InGaN, InAlN, or AlInGaN.
 3. Radiation-emittingsemiconductor component pursuant to claim 1 or 2, characterized by thefact that the reflector (6) is composed of a reflecting metallic contactsurface.
 4. Radiation-emitting semiconductor component pursuant to claim3, characterized by the fact that the contact surface consists of Ag,Al, or an Ag or Al alloy.
 5. Radiation-emitting semiconductor componentpursuant to claim 1 or 2, characterized by the fact that the reflector(6) is made by dielectric vapor deposition, preferably that thedielectric vapor deposition is composed of a plurality of dielectriclayers.
 6. Radiation-emitting semiconductor component pursuant to claim1 or 2, characterized by the fact that the reflector (6) has atransparent first layer applied to the second principal surface (4) anda second reflecting layer applied to this one.
 7. Radiation-emittingsemiconductor component pursuant to one of the claims 1 to 7,characterized by the fact that the entire free surface of thesemiconductor body or a subregion thereof is roughened.
 8. Method forproducing a radiation-emitting semiconductor component whosesemiconductor body is made up of a stack of different III-V nitridesemiconductor layers (1) and that has a first principal surface (3) anda second principal surface (4), with at least a portion of the radiation(5) produced being emitted through the first principal surface (3) andwith the second principal surface (4) having a reflector (6),characterized by the steps application of an interlayer (9) on asubstrate (8) application of a plurality of different III-V nitridesemiconductor layers (1) on the interlayer (9) detachment of thesubstrate (8) including the interlayer (9) application of the reflector(6) on the second principal surface (4) of the semiconductor body. 9.Method pursuant to claim 8, characterized by the fact that an Sisubstrate is used as the substrate (8).
 10. Method pursuant to claim 8or 9, characterized by the fact that an SiC interlayer is applied. 11.Method pursuant to claim 8 to 10, characterized by the fact that theinterlayer (9) is applied by a wafer-bonding method.
 12. Method pursuantto claim 8 to 10, characterized by the fact that the interlayer (9) isapplied by epitaxy.
 13. Method pursuant to claim 8 to 12, characterizedby the fact that the reflector (6) is made by applying a layer of metal,which serves for contacting the semiconductor body at the same time. 14.Method pursuant to one of the claims 8 to 13, characterized by the factthat a mask (11) is applied to the interlayer (9) before producing theGaN layers (1).
 15. Method pursuant to one of the claims 8 to 14,characterized by the fact that the semiconductor body is roughened. 16.Method pursuant to claim 15, characterized by the fact that thesemiconductor body is roughened by etching.
 17. Method pursuant to claim15, characterized by the fact that the semiconductor body is roughenedby a sand-blasting method.
 18. Method for producing a radiation-emittingsemiconductor component whose semiconductor body is made up of a stackof different III-V nitride semiconductor layers (1) and that has a firstprincipal surface and a second principal surface, with at least aportion of the radiation produced being emitted through the firstprincipal surface, and with the second principal surface having areflector, characterized by the fact that the III-V nitride layers areapplied to a composite substrate that has a substrate body and aninterlayer, with the coefficient of thermal expansion of the substratebody being similar to or preferably greater than the coefficient ofthermal expansion of the III-V nitride layers, and with the III-Vnitride layers being deposited on the interlayer.
 19. Method pursuant toclaim 18, characterized by the fact that the thickness of the interlayeris so small that the coefficient of thermal expansion of the compositesubstrate is determined essentially by the substrate body.
 20. Methodpursuant to claim 18 or 19, characterized by the fact that the substratebody contains SiC, poly-SiC, sapphire, GaN, or AlN.
 21. Method pursuantto one of the claims 18 to 20, characterized by the fact that theinterlayer contains SiC, silicon, sapphire, MgO, GaN, or AlGaN. 22.Method pursuant to one of the claims 18 to 21, characterized by the factthat the interlayer has a monocrystalline surface at least insubregions.
 23. Method pursuant to one of the claims 18 to 22,characterized by the fact that the III-V nitride layers are deposited onan Si(111) surface or on an SiC surface of the interlayer that ismonocrystalline at least in subregions.
 24. Method pursuant to one ofthe claims 18 to 23, characterized by the fact that the interlayer isapplied to the substrate body by a wafer-bonding method.
 25. Methodpursuant to one of the claims 18 to 24, characterized by the fact that abonding layer is produced between the substrate body and the interlayer.26. Method pursuant to claim 25, characterized by the fact that thebonding layer contains silicon oxide.
 27. Method pursuant to one of theclaims 18 to 26, characterized by the fact that a mask layer is producedwith epitaxy windows on the composite substrate before applying theIII-V nitride layers, with the epitaxy surface of the compositesubstrate remaining uncovered within the epitaxy windows.
 28. Methodpursuant to one of the claims 18 to 27, characterized by the fact thatthe III-V nitride layers are structured into individual semiconductorlayer stacks after being applied to the composite substrate.
 29. Methodpursuant to claim 28, characterized by the fact that the method iscontinued with the steps: application of a carrier to the semiconductorlayer stack, detachment of the composite substrate.
 30. Method pursuantto claim 28, characterized by the fact that the method is continued withthe steps: application of an interlayer on the semiconductor layerstack, detachment of the composite substrate, application of a carrierto the side of the semiconductor layer stack from which the compositesubstrate has been detached, detachment of the interlayer.
 31. Methodpursuant to one of the claims 28 to 30, characterized by the fact that areflector layer is produced on the semiconductor layer stack.
 32. Methodpursuant to claim 31, characterized by the fact that the reflector layeris produced by applying a metallic layer.
 33. Method pursuant to claim32, characterized by the fact that the metallic layer contains silver,aluminum or a silver or aluminum alloy.
 34. Method pursuant to one ofthe claims 31 to 33, characterized by the fact that the reflector layerserves as a contact surface at the same time.
 35. Method pursuant toclaim 31, characterized by the fact that the reflector layer is producedby dielectric vapor deposition.
 36. Method pursuant to claim 31,characterized by the fact that the reflector layer is produced byapplying a transparent first layer to the semiconductor layer stack andapplying a reflecting second layer to the first layer.
 37. Methodpursuant to one of the claims 28 to 36, characterized by the fact thatthe surface of the semiconductor layer stack is roughened at leastregionally.
 38. Method pursuant to claim 37, characterized by the factthat the surface of the semiconductor layer stack is roughened byetching.
 39. Method pursuant to claim 37, characterized by the fact thatthe surface of the semiconductor layer stack is roughened by asand-blasting method.